Windows 10 uses more than 5GB of host space when running on Fusion 7.1.2

[BenSchoenfeld]

I lose 5GB of hard drive space on my main drive when I start my Windows 10 VM on Fusion 7.1.2. When I drop below 5GB of free space on my host, Fusion stops the VM because there's not enough space left. So I have to have more than 10GB free on my host drive just to run my VM. That's tough to swallow on a MacBook Air with a 256GB SSD when the VM already takes more than 50 GB.

Is this normal and I just never noticed it when running Fusion 6 and Windows 8.1, or is there a way to keep it from taking so much space?

[wila · Accepted solution]

Hi,

It depends a bit on how much RAM you assigned to the VM. If you assign 5GB of RAM to the VM then Fusion will create a disk file of 5GB on bootup to back that RAM. There are vmx settings to turn that feature off, but it isn't recommended or supported.

--
Wil

[Pbryanw]

I'm just wondering if you did an upgrade to Windows 10 from 8.1.

If that's the case you can reclaim a good portion of your hard-drive space back by using the Windows disk clean-up utility to remove Windows 10 installation files (which can take up to 10Gb of space).

Then go to that VM's General Settings and there should a button to reclaim that space back for OS X (I'm unsure of the exact settings as I'm not in front of my Mac).

Of course, if you do this, (and providing you can do this) you won't be able to rollback to Windows 8.1 if you have any major problems with Windows 10.